Electrically synchronized controllers

ABSTRACT

A multiple hand controller system is disclosed having redundant systems for synchronizing the movements of the hand controllers. In one embodiment, the hand controller system comprises a pair of movable hand controllers. Each hand controller is coupled to a movable ground point to be movable in two modes. The first mode is where the hand controller moves with respect to its ground point. The second mode is where the hand controller moves as a unit with its ground point. The synchronizing system comprises two sets of components. Each set includes an actuator for varying the location of the ground point of one hand controller. Each set includes a first sensor for sensing the first mode of movement for one hand controller and generating an input signal porportional to this movement. The input signal from the first sensor of each set is fed, through a summing amplifier, to the actuator of the other set. A second sensor is also provided for monitoring the movement of each ground point and generating a signal proportional to this movement. The signal from each second sensor is fed back to the summing amplifier controlling its respective actuator to be algebraically summed with the input signal from the first sensor to generate an output signal. This output signal is fed to the respective actuator to command the actuator to move the ground point location of its connected hand controller an amount representative of the movement of the other hand controller. This cross synchronization enables the movement of one hand controller in the first mode to affect a representative movement of the other hand controller in the second mode.

United States Patent 1 Buscher et al.

[451 July 31,1973

[ ELECTRICALLY SY NCHRONIZED CONTROLLERS Primary Examiner-Wm. H. GriebAttorney-Harold L. Jackson et al.

[57] ABSTRACT A multiple hand controller system is disclosed havingredundant systems for synchronizing the movements of the handcontrollers. In one embodiment, the hand controller system comprises apair of movable hand controllers. Each hand controller is coupled to amovable ground point to be movable in two modes. The first mode is wherethe hand controller moves with respect to its ground point. The secondmode is where the hand controller moves as a unit with its ground point.The synchronizing system comprises two sets of components. Each setincludes an actuator for varying the location of the ground point of onehand controller. Each set includes a first sensor for sensing the firstmode of movement for one hand controller and generating an input signalporportional to this movement. The input signal from the first sensor ofeach set is fed, through a summing amplifier, to the actuator of theother set. A second sensor is also provided for monitoring the movementof each ground point and generating a signal proportional to thismovement. The signal from each second sensor is fed back to the summingamplifier controlling its respective actuator to be algebraically summedwith the input signal from the first sensor to generate an outputsignal. This output signal is fed to the respective actuator to commandthe actuator to move the ground point location of its connected handcontroller an amount representative of the movement of the other handcontroller. This cross synchronization enables the movement of one handcontroller in the first mode to afiect a representative movement of theother hand controller in the second mode.

26 Claims, 4 Drawing Figures 7 mwma j 3 2 mwpfp 551/50? 0 0 V Z W 2arm/0e g z; 4 a; jz/mm/a 4} a; fix/ma 47 5 4 7 67 2 Wm 4f 7 7g 144/4 /06! 47 7 47 w 7/ 74 iii by a; #[0545/ PATENIED JUL 3 I I973 SHEET 1 [IF 4PATENIE JUL3 I ma SHEET 2 OF 4 ELECTRICALLY SYNCHRONIZED CONTROLLERSBACKGROUND OF THE INVENTION:

1. Field of the Invention The present invention relates generally tomultiple hand controllers for transmitting output commands, and moreparticularly to the means for synchronizing the movement of the handcontrollers.

2. Description of the Prior Art Many systems utilize multiple handcontrollers for transmitting commands to an output network. A typicalexample can be found in multiple steering systems utilized in drivereducation courses. In such a system, a number of synchronized steeringwheels are provided for simultaneously steering imaginary vehicles overa simulated track shown on a screen. One of the steering wheels ismanned by the instructor so that all others manned by the students getthe feel of the instructors own steering movements.

Heretofore, the synchronization of such dual control systems wasaccomplished by mechanical means. That is, a mechanical linkage wasprovided between the two controllers to transmit the movement of onecontroller to that of the other.

Such mechanical systems function adequately when the controllers arestationed a very short distance away from each other. However, if thecontrollers are separated a substantial distance from each other, thelinkage mechanism becomes quite complicated. It has been found that suchlinkages lose their reliability when they become overly complex.

SUMMARY OF THE INVENTION:

The present invention obviates this shortcoming by providing a multiplehand controller system having an electro-mechanical synchronizationsystem that can function effectively in any type of controllerarrangement.

In its broadest aspect, the system comprises more than one movable handcontroller for transmitting an output command to an output network. Thesynchronization system includes a sensor for sensing the move.- ment ofeach hand controller and generating a signal proportional to thismovement. The system also includes an actuator for moving each handcontroller. The sensors and actuators are cross-connected in such amanner that the signal from the sensor of one hand controller is appliedto the actuator of each of the other hand controllers to command theactuator to move its connected hand controller an amount representativeof the movement of the one controller.

A primary advantage of the preferred embodiment of thepresent inventionis that electrical-mechanical and electrical signal connections betweenthe sensors and the actuators can be easily made, no matter how farapart the hand controllers are.

Another advantage of the present invention is that the signal generatedby the sensors can also be utilized in generating an output command.

The'features of'the present invention which are believed to be novel areset forth with particularity in the appended claims. The presentinvention, both as to its organization and manner of operation, togetherwith further objects and advantages thereof, may best be understood byreference to the following description, taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of amultiple hand controller system of the present invention;

FIG. 2 is a schematic view of the hand controller system shown in asecond position;

FIG. 3 is a schematic view of the hand controller system shown in athird position; and I FIG. 4 is a schematic view of the hand controllersystem shown being returned from a fourth position to the aforementionedsecond position.

DESCRIPTION OF THE PREFERRED EMBODIMENT:

Referring now to the drawings, FIG. 1 illustrates a multiple handcontroller system, generally indicated by arrow 10, having a pair ofhand levers or controllers 11 and 13 pivotally mounted on a pair ofground pivot points 15. The hand controllers 11 and 13 are adapted to belocated at the operators control stations which can be arranged in anyconfiguration. For example, the stations may be positioned fore and aft,in a side-byside relationship, or remote from each other.

The hand controllers l1 and 13 are connected to a pair of movable groundpoints 17 and 19 via a pair of flexible transmission systems 21 and 23.Each transmission system comprises a first rigid bar 25 pivotallyconnected'at one end to a respective hand controller 11 and 13. Theother ends of the bars 25 are connected to a pair of springs 29 and 31which, in turn, are connected to a second pair of rigid bars 33.

Each hand controller 11 and 13 is adapted to be moved fore and aft toeither elongate or shorten the springs 29 and 31 with respect to theground points 17 and 19. A damper 37 is connected to each pair of bars25 and 33 via linkages 41. The dampers 37 can be of any conventionalconstruction, such as a hydraulic piston and cylinder arrangement, witheach damper 37 functioning in the conventional manner to dampen themovement of its respective spring.

The elongation and contraction of the springs 29 and 31 with respect totheir ground points 17 and 19 are measured by a pair of sensing means astypified by a linear voltage differential transducer 43 and 45. Eachtransducer is interconnected via linkages 47, to the bars 25 and 33 andis constructed to provide a voltage signal that is linearly proportionalto the relative movement of these bars.

The mechanical ground points 17 and 19 are connected to a pair ofactuators 49 and 51 through linkages 53 to be moved thereby. Eachactuator is also connected to a mechanical ground point 55 via linkages56. As with the other components, the actuators 49 and 51 can be of anyconventional construction, such as an electrically operated hydraulicram, or a solenoid type servo motor.

The operation of the actuators 49 and 51 are monitored by a pair oflinear voltage differential transducers 57 and 59. In effect, thetransducers 57 and 59 function to sense the relative movement of themovable ground points 17 and 19 with their fixed ground points 55. Thetransducers 57 and 59 are similar in construction to the transducers 43and 45, and are interconnected to the linkages 53 and the ground points55 by linkages 61 to provide a feedback voltage signal that is linearlyproportional to the relative movement of these members.

A pair of summing amplifiers 63 and 65 are provided to cross connect thetransducers 43 and 45 with the actuators 51 and 49 respectively.Electrical lines 67 and 69 are utilized to interconnect the transducers43 and 45 with the amplifiers 63 and 65, while electrical lines 71 and73 interconnect the amplifiers 63 and 65 with the actuators 51 and 49.

The transducers 57 and 59 are also connected to the amplifiers 65 and 63respectively via lines 75 and 77. Amplifiers 63 and 65 are jointlyconnected to an input terminal 83 for receiving input signals responsiveto external conditions or commands. For example, the input signal onterminal 83 may come from a third hand controller. If such a controllerwere employed, it would be identical in configuration to either one ofthe pair of hand controllers shown in the figures. Similarly, theelectrical signals from the pair would be brought to the electricalsumming amplifiers as described hereinbefore. In short, any number ofsuch hand controllers may be interconnected within the spirit and scopeof the invention.

Finally, the lines 67 and 69 are also connected to an output amplifier85 to provide anoutput command to an output network.

OPERATION For explanatory purposes, the position of the hand controllers11 and 13 shown in FIG. 1 will be called the neutral or zero position.This is the position that the controllers would assume when no outsideforce is applied thereto.

In operation, the two operators are positioned at their stations tomanually and simultaneously control the movement of the hand controllersto provide an output command to an output network.

Referring now to FIG. 2, assuming the first operator wishes to create acertain output command, he would move the hand controller 11 forwardfrom the neutral zero position. Although this movement could be anyamount to effect the desired change, let us assume that the operatorapplies a five pound force to the controller 11 to move the controller11 from the zero position to a first position. It is further assumedthat the successive positions are divided into pound force increments,merely for explanatory purposes. In moving to the first position, theground point 17 remains fixed, at GP and the hand controller 11functions to elongate the spring 29. When this occurs, the transducer 43senses this elongation and generates an input signal proportional tothis movement. This input signal is then transmitted simultaneously tothe output amplifier 85 and to the summing amplifier 63 as anon-inverted input signal. As stated previously, a feedback signal fromthe transducer 59 is also fed back to the amplifier 63 to indicate thelocation of the ground point 19. The amplifier functions toalgebraically sum these signals by arithmetically subtracting thefeedback signal from the noninverted signal until the output signal isnulled.

Let us assume that the input signal proportional to the movement of thespring 29 is calibrated to be given a +1 value with each incrementalpositional movement proportional to a value of l. This signal is fedthrough the summing amplifier 63 to command the actuator 51 to move thefixed point 19 forward from a point designated GP Since the actuator 51has not moved from its neutral position, the original feedback signalfrom the transducer 59 will be assumed to be a zero value.

This zero value is subtracted from the +1 value to pro duce the +1output signal described above. Thereafter,

the continuous movement of the actuator 51 and the ground point 19 inthe forward direction is sensed by the transducer 59. The continuallychanging feedback signal is fed into the amplifier 63 until the signalreaches a +1 value to null the input signal from the transducer 43. Whenthis occurs, the actuator 51 is deenergized to stop the movement of theground point 19. At this point, the movement of the ground point 19 willhave moved from GP to GP This movement is transmitted through thetransmission 23 to the hand controller 13 to enable them to move as aunit. The total movement of the hand controller 13 in response to theinput signal is calibrated to equal the movement of the hand controller11. It should be noted that the output signal can be calibrated toproduce any amount of movement in the hand controller 13 that isrepresentative of the movement of the hand controller 11.

In this first position, the holding force of five pounds is applied bythe first operator to maintain the hand controllers 11 and 13 in thatposition. No force is applied by the second operator, although he cansense this movement because of the force of the actuator 51 beingapplied to his hand controller..

Referring now to FIG. 3, let us assume that the second operator nowwishes to move the hand controller 13 forward from the first position toa second position. He would then move the hand controller 13 forward byapplying a five pound force thereto. When this occurs, the handcontroller 13 is moved away from the ground point 19, now at GP Theelongation of the spring 31 is then sensed by the transducer 45 tosimultaneously transmit an input signal to the output amplifier and thesumming amplifier 65. The input signal, which is proportional to theincremental movement of the spring 31, is given the value of +1 for thereason given above and is fed into the summing applifier 65. As'before,this signal is fed through the summing amplifier 65 to command theactuator 49 to move the fixed point 17 forward from the point designatedGP Since the actuator 49 and ground point 17 are originally at the zeroor GP position, the feedback signal from the transducer 57 is a zerovalue and is also fed into the summing amplifier 65. This value issubtracted from the +1 value of the transducer 45 to give a net outputsignal of +1. Thereaftenthe continually changing feedback signal fromthe transducer 57, due to the movement of the actuator 49, is fed intothe amplifier 65 until the feedback signal reaches a +1 value to nullthe input signal from the transducer 45. When this occurs, the actuator49 is de-energized to stop the movement of the ground point 19. At thispoint, the movement of the ground point 19 will have moved from GP toGP,. This movement is such to enable the hand controller I] and thetransmission 21 to move forward as a unit to the new position 2 alreadyacquired by controller 13. As this occurs, the first operator sensesthis movement and is able to monitor the operation of the secondoperator. In thisposition, both operators are applying a five poundforce on their respective hand controllers.

Let us assume that the first operator now wishes to move the handcontroller 1 I from position 2 to position 3. The input signal from thetransducer 43 sensing the additional elongation of the spring 29 willhave a value of +2 (equal to a 10 pound force). The original feedbacksignal from the transducer 59 will be a +1 since the ground point 19 hasmoved from GE, to be presently located at GP This .+l signal value issubtracted from the +2 of the transducer 43 to result in a +1 outputsignal to command the actuator 51 to move the ground point 19 forwarduntil the feedback signal equals a +2. At this point, the ground point19 will have moved to a new position GP which is the amount necessary toenable the hand controller 13 and the transmission 23 to move forward asa unit to position 3. This third position is shown in FIG. 4.

Assuming both hand controllers are now in position 3, and the firstoperator wishes to return his hand controller to position 1, he wouldfirst release his ten pound holding force on the hand controller 11 toallow .the spring 29 to shorten to its original length. The

movement is sensed by the transducer 43 which, emits a signal having avalue of since the spring has moved through a distance equal to twopositions back to its original position. Since the ground point 19 is atGP the +2 feedback signal is subtracted from 0 input signal at theamplifier 63 to give a 2 output signal. As a result, the actuator iscommanded to move the ground point 19 rearward from the position (3Puntil the feedback signal equals the zero value input signal. At thispoint, the ground point 19 will have moved from GP to GP to enable thehand controller 13 and the transmission 23'to be moved as a unit toposition 1. The movement described above is shown in FIG. 4. In, thisfirst position, the only force applied to the system is the pound forceby the second operator.

It should be noted that both types of movement can occur simultaneously.For example, both operators can apply a 5 pound force to their handcontrollers. In this instance each hand controller will move relative toits ground point one positional increment with the generated inputsingals moving both ground points to enable both controllers to move asa unit with their ground points one incremental position.

It should also be noted that at any time, the input signal from terminal83, which is responsive to external conditions, can be applied to give acorrectional command to the summing amplifiers 63 and -65. As statedpreviously, an additional hand controller system identical to the onedescribed can also be employed to provide such an input-signal.Moreover, although two hand controller systems are illustrated, anynumber of systems can be utilized with the input signal from themovement of each hand controller being fed to all of the other handcontroller actuators to move the ground points of the other handcontrollers. The respective feedback systems for each actuator willmonitor the movement of the actuator until the actual location of theground point agrees with that of the input command.

Moreover, although an electrical synchronizing system is shown, ahydraulic system can also be utilized in the system in accordance withthe present invention. In this embodiment, hydraulic servos and lineswould replace the electrical servos and lines shown in the drawings. Inaddition, fluid amplifiers would be utilized to algebraically sum thehydraulic input signals from the hydraulic sensors and the hydraulicfeedback signals from the hydraulic feedback sensors.

It would also be within the purview of the present invention for thehand controllers to rotate such as steering wheels. In thisconfiguration, the steering wheels would rotate with respect to amovable ground position, with the sensors measuring the angular movementof the wheels. 7

As can be seen, a multiple hand controller system is provided in which asynchronizing system is utilized to synchronize the movement of the handcontrollers to enable each operator to sense the controlling movementsof the other operators. The primary importance of this system is thatthe lines interconnecting the various components enable the componentsand hence the operating stations to be remotely positioned-a greatdistance with respect to each other. 1

It should be noted that various modifications can be made to theapparatus while still remaining within the purview of the followingclaims.

What is claimed is: comprising:

1. A multiple interconnected control system comprising:

a number of movable controllers for transmitting an output command to anoutput network;

a movable reference ground point for each controller, each controllerbeing operatively connected to a respective movable ground point to moveas a unit with said movable ground point, each controller further beingmovable relative to its connected movable ground point;

means for sensing the movement of each controller and generating aninput signal proportional to this movement; and actuator means formoving each controller, the actuator means of its connected controllerbeing responsive to the signal from the sensing means of each of theother controllers for moving its connected controller an amountrepresentative of the movement of the respective other controllers.

2. The invention of claim 1 further comprising resilient means forinterconnecting each controller with its respective movable groundpoint, each controller being manually operable by an operator.

3. The invention of claim 1 wherein each of said actuator means isoperatively connected to a fixed ground point for moving said movableground point.

4. The invention of claim 3 further comprising feed back means forsensing the movement of each movable ground point and generating afeedback signal proportional to this movement.

5. The invention of claim 3 wherein each of said feedback meanscomprises a linear voltage differential transducer capable of generatingvoltage input signals.

6. The inventionof claim 4 further comprising summing means forreceiving the input signals from each of the sensing means of the othercontrollers and the feedback signal from the feedback means sensing themovable ground point location of the one controller, said summing meansalgebraically summing said voltage sig nals to generate an outputsignal.

7. The invention of claim 6 wherein said summing means is connected tothe actuator moving the movable ground point of the one controller forcommanding said actuator to move said movable ground point an amountrelated to said output signal.

8. The invention of claim 6 further including means responsive toexterior conditions and commands for feeding a correctional signal toeach of said summing means.

9. The invention of claim 7 wherein said summing means comprises asumming amplifier.

10. The invention of claim 1 further comprising a spring interconnectingeach controller with its respective movable ground point.

11. The invention of claim 10 wherein each of said sensing meanscomprises means for sensing the elongation of said spring with respectto its respective movable ground point connection.

12. The invention of claim 11 wherein each of said electro-mechanicalsensing means comprises a linear voltage differential transducer capableof generating voltage input signals.

13. The invention of claim 1 further comprising an output amplifier forreceiving the signals from said sensing means and generating an outputsignal in response to said input signals.

14. In a multiple controller system comprising:

at least a pair of movable controllers;

a pair of movable ground points, respectively connected to saidcontrollers;

first actuator means for moving one controller in response to an inputsignal;

second actuator means for moving the other controller in response to aninput signal;

first sensing means for sensing the movement of the one controller andgenerating an input signal proportional to this movement;

second sensing means for sensing the movement of the other controllerand generating an input signal proportional to this movement; and

means for interconnecting said first actuator means with said secondsensing means to enable the second sensing means to apply an inputsignal to the first actuator means to move the one controller an amountrepresentative of the movement of the other controller, at least onecontroller capable of moving both with its respective movable groundpoint and also moving relative to the respective movable ground point.

15. The invention of claim 14 further comprising means forinterconnecting said second actuating means with said first sensingmeans to enable the first sensing means to apply an input signal to thesecond actuator means to move the other controller an amountrepresentative of the movement of the one controller.

16. The invention of claim 15 wherein each of said sensing means arecapable of sensing the movement of each controller with respect to itsconnected movable ground point.

17. The invention of claim 15 wherein each of said actuator means isoperatively connected to a respective movable ground point for movingsaid movable ground point and controller as a unit.

18. The invention of claim 27 further comprising first and secondfeedback means for respectively sensing the movement of said first andsecond actuator means and generating feedback signals proportional tothe respective movements of the actuator means.

19. The invention of claim 18 further comprising first summing means forreceiving the input signal from the first sensing means and the feedbacksignal of the second feedback means, said first summing meansalgebraically summing the two signals for generating an output signalwhich is applied to the second actuator means for commanding said secondactuator means to move its connected movable ground point in response tosaid output signal.

20. The invention of claim 19 wherein said first summing means comprisesa summing amplifier.

21. The invention of claim 18 further comprising second summing meansfor receiving the input signal from the second sensing means and thefeedback signal from said first feedback means, said second summingmeans algebraically summing the two signals for generating an outputsignal which 'is applied to the first actuator means for commanding saidfirst actuator means to move its connected movable ground point inresponse to said output signal.

22. The invention of claim 21 wherein said second summing meanscomprises a summing amplifier.

23. The invention of claim 18 wherein said first and second feedbackmeans comprise a pair of linear voltage differential transducers forgenerating feedback voltage signals.

24. The invention of claim 14 wherein said first and second sensingmeans comprise a pair of linear voltage differential transducers forgenerating input voltage signals.

25. In a hand controller system comprising:

a pair of movable hand controllers;

a pair of movable reference ground points connected respectively to saidhand controllers;

first actuator means for moving one hand controller in response to aninput signal;

second actuator means for moving the other hand controller in responseto an input signal;

first sensing means including a first linear voltage differentialtransducer for sensing the movement of the one hand controller andgenerating an input signal proportional to this movement; second sensingmeans including a second linear voltage differential transducer forsensing the move ment of the other hand controller and generating aninput signal proportional to this movement; and

means for interconnecting said first actuating means with said secondsensing means to enable the second sensing means to apply an inputsignal to the first actuator means to move the one hand controller anamount representative of the movement of the other hand controller andmeans for interconnecting said second actuating means with said firstsensing means to enable the first sensing means to apply an input signalto the second actuator means to move the other hand controller an amountrepresentative of the movement of the other hand controller.

26. In a hand controller system comprising:

a pair of movable hand controllers;

a pair of movable ground points respectively connected to said handcontrollers;

first actuator means for moving one hand controller in response to aninput signal;

second actuator means for moving the other hand controller in responseto an input signal, each of said actuator means is operatively connectedto a respective movable ground point for moving said movable groundpoint and hand controller as a unit;

first and second feedback means for respectively sensing the movement ofsaid first and second actuator means and generating feedback signalsproportional to the respective movements of the actuator means;

first sensing means for sensing the movement of the one hand controllerand generating an input signal proportional to this movement;

second sensing means for sensing the movement of the other handcontroller and generating an input signal proportional to this movement;and

means for interconnecting said first actuating means with said secondsensing means to enable the second sensing means to apply an inputsignal to the first actuator means to move the one hand controller anamount representative of the movement of the other hand controller;

means for interconnecting said second actuating means with said firstsensing means to enable the 10 first sensing means to apply an inputsignal ,to the second actuator means to move the other hand controlleran amount representative of the movement of the one hand controller andfirst summing means for receiving the input signal from the firstsensing means and the feedback signal of the second feedback means, saidfirst sum- 1 ming means algebraically summing the two signals forgenerating an output signal which is applied to the second actuatormeans for commanding said second actuator means to move its connectedmovable ground point in response to said output signal.

UNITED STATES PATENT OFFICE CERTlFICATE CGRRECTION Patent No. 3 748, 749D t d July 31, 1973 Inventor) Richerd G. Buscher and Richard L Davis Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 6, line 15, "comprising: sboulol be deleted.

Column 7, line. 54, "27" Should be "17".

Signed and sealed this 25th day of December 1973.

(SEAL) ,Attest:

EDWARD M.FLET0RRR, JR. RENE D. TEGTMRYER Attesting Officer ActingCommissioner of Patents FORM F'O-IOSO r1o-s9) I USCOMM- DC suave-Pea(llLS. GOVERNMENT PRINTING OFFICE: l9? 0-366-53,

1. A multiple interconnected control system comprising: a number ofmovable controllers for transmitting an output command to an outputnetwork; a movable reference ground point for each controller, eachcontroller being operatively connected to a respective movable groundpoint to move as a unit with said movable ground point, each controllerfurther being movable relative to its connected movable ground point;means for sensing the movement of each controller and generating aninput signal proportional to this movement; and actuator means formoving each controller, the actuator means of its connected controllerbeing responsive to the signal from the sensing means of each of theother controllers for moving its connected controller an amountrepresentative of the movement of the respective other controllers. 2.The invention of claim 1 further comprising resilient means forinterconnecting each controller with its respective movable groundpoint, each controller being manually operable by an operator.
 3. Theinvention of claim 1 wherein each of said actuator means is operativelyconnected to a fixed ground point for moving said movable ground point.4. The invention of claim 3 further comprising feedback means forsensing the movement of each movable ground point and generating afeedback signal proportional to this movement.
 5. The invention of claim3 wherein each of said feedback means comprises a linear voltagedifferential transducer capable of generating voltage input signals. 6.The invention of claim 4 further comprising summing means for receivingthe input signals from each of the sensing means of the othercontrollers and the feedback signal from the feedback means sensing themovable ground point location of the one controller, said summing meansalgebraically summing said voltage signals to generate an output signal.7. The invention of claim 6 wherein said summing means is connected tothe actuator moving the movable ground point of the one controller forcommanding said actuator to move said movable ground point an amountrelated to said output signal.
 8. The invention of claim 6 furtherincluding means responsive to exterior conditions and commands forfeeding a correctional signal to each of said summing means.
 9. Theinvention of claim 7 wherein said summing means comprises a summingamplifier.
 10. The invention of claim 1 further comprising a springinterconnecting each controller with its respective movable groundpoint.
 11. The invention of claim 10 wherein each of said sensing meanscomprises means for sensing the elongation of said spring with respectto its respective movable ground point connection.
 12. The invention ofclaim 11 wherein each of said electro-mechanical sensing means comprisesa linear voltage differential transducer capable of generating voltageinput signals.
 13. The invention of claim 1 further comprising an outputamplifier for receiving the signals from said sensing means andgenerating an output signal in response to said input signals.
 14. In amultiple controller system comprising: at least a pair of movablecontrollers; a pair of movable ground points, respectively connected tosaid controllers; first actuator means for moving one controller inresponse to an input signal; second actuator means for moving the othercontroller in response to an input signal; first sensing means forsensing the movement of the one controller and generating an inputsignal proportional to this movement; second sensing means for sensingthe movement of the other controller and generating an input signalproportional to this movement; and means for interconnecting said firstactuator means with said second sensing means to enable the secondsensing means to apply an input signal to the first actuator means tomove the one controller an amount representative of the movement of theother controller, at least one controller capable of moving bOth withits respective movable ground point and also moving relative to therespective movable ground point.
 15. The invention of claim 14 furthercomprising means for interconnecting said second actuating means withsaid first sensing means to enable the first sensing means to apply aninput signal to the second actuator means to move the other controlleran amount representative of the movement of the one controller.
 16. Theinvention of claim 15 wherein each of said sensing means are capable ofsensing the movement of each controller with respect to its connectedmovable ground point.
 17. The invention of claim 15 wherein each of saidactuator means is operatively connected to a respective movable groundpoint for moving said movable ground point and controller as a unit. 18.The invention of claim 27 further comprising first and second feedbackmeans for respectively sensing the movement of said first and secondactuator means and generating feedback signals proportional to therespective movements of the actuator means.
 19. The invention of claim18 further comprising first summing means for receiving the input signalfrom the first sensing means and the feedback signal of the secondfeedback means, said first summing means algebraically summing the twosignals for generating an output signal which is applied to the secondactuator means for commanding said second actuator means to move itsconnected movable ground point in response to said output signal. 20.The invention of claim 19 wherein said first summing means comprises asumming amplifier.
 21. The invention of claim 18 further comprisingsecond summing means for receiving the input signal from the secondsensing means and the feedback signal from said first feedback means,said second summing means algebraically summing the two signals forgenerating an output signal which is applied to the first actuator meansfor commanding said first actuator means to move its connected movableground point in response to said output signal.
 22. The invention ofclaim 21 wherein said second summing means comprises a summingamplifier.
 23. The invention of claim 18 wherein said first and secondfeedback means comprise a pair of linear voltage differentialtransducers for generating feedback voltage signals.
 24. The inventionof claim 14 wherein said first and second sensing means comprise a pairof linear voltage differential transducers for generating input voltagesignals.
 25. In a hand controller system comprising: a pair of movablehand controllers; a pair of movable reference ground points connectedrespectively to said hand controllers; first actuator means for movingone hand controller in response to an input signal; second actuatormeans for moving the other hand controller in response to an inputsignal; first sensing means including a first linear voltagedifferential transducer for sensing the movement of the one handcontroller and generating an input signal proportional to this movement;second sensing means including a second linear voltage differentialtransducer for sensing the movement of the other hand controller andgenerating an input signal proportional to this movement; and means forinterconnecting said first actuating means with said second sensingmeans to enable the second sensing means to apply an input signal to thefirst actuator means to move the one hand controller an amountrepresentative of the movement of the other hand controller and meansfor interconnecting said second actuating means with said first sensingmeans to enable the first sensing means to apply an input signal to thesecond actuator means to move the other hand controller an amountrepresentative of the movement of the other hand controller.
 26. In ahand controller system comprising: a pair of movable hand controllers; apair of movable ground points respectively connected to said handcontrollers; first actuator means for moving one haNd controller inresponse to an input signal; second actuator means for moving the otherhand controller in response to an input signal, each of said actuatormeans is operatively connected to a respective movable ground point formoving said movable ground point and hand controller as a unit; firstand second feedback means for respectively sensing the movement of saidfirst and second actuator means and generating feedback signalsproportional to the respective movements of the actuator means; firstsensing means for sensing the movement of the one hand controller andgenerating an input signal proportional to this movement; second sensingmeans for sensing the movement of the other hand controller andgenerating an input signal proportional to this movement; and means forinterconnecting said first actuating means with said second sensingmeans to enable the second sensing means to apply an input signal to thefirst actuator means to move the one hand controller an amountrepresentative of the movement of the other hand controller; means forinterconnecting said second actuating means with said first sensingmeans to enable the first sensing means to apply an input signal to thesecond actuator means to move the other hand controller an amountrepresentative of the movement of the one hand controller and firstsumming means for receiving the input signal from the first sensingmeans and the feedback signal of the second feedback means, said firstsumming means algebraically summing the two signals for generating anoutput signal which is applied to the second actuator means forcommanding said second actuator means to move its connected movableground point in response to said output signal.